Things took another bad turn for the U.S. intelligence and law-enforcement community as Reuters reported yesterday that U.S. officials put Tamerlan Tsarnaev, the accused instigator of the Boston Marathon bombing who was killed during the manhunt last week, on one of the U.S. databases of potential terrorists 18 months before he and his brother allegedly launched the attack.

That revelation has prompted an unsurprising response from Capitol Hill. Asked if Homeland Security Secretary Janet Napolitano was responsible for not tracking Tsarnaev before the bombing, Lindsey Graham told CNN on Thursday, “I have no idea who bears the blame, I just know the system is broken. The ultimate blame I think is with the Administration.”

House Homeland Security Chairman Michael McCaul, initially cautious in his response to the bombing, is growing increasingly critical of the performance of government agencies as well. At a Washington intelligence conference on Thursday, McCaul said Tsarnaev’s “departure from the U.S. would warrant a second look.”

The more indications emerge that the elder Tsarnaev had come to the attention of U.S. officials before the bombing, the stronger the case becomes that law enforcement could have convinced a judge to allow the FBI to monitor him for signs he intended to do something violent.

But that doesn’t mean we know for sure that the FBI or Department of Homeland Security or some other government agency dropped the ball. The U.S. Director of National Intelligence, James Clapper, told the same conference that Americans should “not hyperventilate for a while before we get all the facts.” With regard to the handling of the Tsarnaevs by law enforcement and the intelligence community before the attack, Clapper said, “The rules were abided by, as best as I can tell at this point … the dots were connected.”

Even more robust in his defense of U.S. law enforcement and intelligence was Philip Mudd, a former top CIA and FBI terrorist hunter, who told a Brookings conference on Wednesday that those labeling the Tsarnaev case an intelligence failure have a “misunderstanding of how national-security operations work in this country.”

Mudd makes a useful distinction between investigating radicalism and violence. Simply knowing someone has radical beliefs doesn’t get you very far, Mudd says. His comments are worth watching:

Fair or not, it seems the post-Boston-bombing blame game is already well under way.